Twitter names new CEO to replace co-founder Evan Williams

Twitter Inc. has just named Dick Costolo, who has been heading the San Francisco microblogging service’s quest to develop new revenue sources, as its new chief executive officer.

Costolo replaces co-founder Evan Williams, who said in a blog post that starting immediately, he will be completely focused on product strategy.”

The move comes just after Twitter redesigned its main website in a way that could create new revenue streams. The executive shakeup could signal Twitter is about to ramp up efforts to really cash in on its growing audience of 165 million registered members.

Williams said he asked Costolo to take the promotion to tak eon the challenges of Twitter’s rapid growth.

“In fact, there are 300 people working at Twitter today – compared to about 20 when I took the CEO job two years ago,” he wrote. “Back then, people were creating about 1.25 million tweets a day-compared to 90 million today. In those same two years, we grew from 3 million registered users to more than 160 million today.”

“This led to a realization as we launched the new Twitter. I am most satisfied while pushing product direction. Building things is my passion, and I’ve never been more excited or optimistic about what we have to build,” Williams wrote.

“When I insisted on bringing Dick into the COO role a year ago, I got a lot of questions from my board. But I knew Dick would be a strong compliment to me, and this has proven to be the case. During his year at Twitter, he has been a critical leader in devising and executing our revenue efforts, while simultaneously and effectively making the trains run on time in the office.”

Costolo, who founded Feedburner, which Google acquired in 2007, said in a statement that he respected Williams’ decision “to focus on product strategy and vision.”

“As we’ve all seen with the new Twitter, when Ev focuses on product, something amazing can happen. I’m certainly excited to be taking on this role,” he said. “You couldn’t ask to take a job like this at a better time – the team is incredible, we have awesome stuff in the pipeline, and we’re ready to accomplish more in the next two years than we’ve accomplished in the last four.”